The general context is that of the application of the ARINC816 standard which imposes a specific format for airport map databases. These airport databases, once compiled in the form of digitized maps, allow aircraft pilots to position themselves on the said digitized airport maps during the takeoff, landing or taxiing phases. Airport databases are produced by specialist companies, called data providers, and must be regularly updated, typically every 28 days.
More precisely, the relevance is to particular elements of these airport databases conforming to the ARINC816 standard: the elements corresponding to taxiways or linkways, more commonly called “taxiway elements”, the term that will be used subsequently. These taxiways are defined as sets of polygons, corresponding to roadways on which the aircraft can taxi and which are not takeoff or landing runways. Each polygon possesses an identity, corresponding to an identifier. The ARINC816 standard specifies that it must be possible to symbolize bridges in a specific and visible manner. Indeed, bridges are crucial elements of airport maps, from the safety point of view. To chart these bridges, the ARINC816 standard stipulates that data providers must indicate where the bridges are situated and whether they are above or below another pathway. Data providers, constrained moreover by the precise detail of the data that they supply, generally give a set of points to characterize a bridge. Such sets of points can constitute complex polygons.
The problem posed is to determine the four characteristic points of a bridge, corresponding substantially to the four corners of the said bridge, on the basis of a complex polygon, and to order them so as to allow correct orientation of the bridge on the corresponding airport map. The objective is to determine, on the basis of the set of points provided, two pairs of characteristic points, each pair of points constituting substantially one side of the bridge.
Currently, to characterize a bridge, data providers therefore provide a set of points that can constitute a complex polygon. The problem is to determine two pairs of correctly ordered points, so as to be able to represent the said bridge correctly on an airport map. No automatic method currently enables this task to be accomplished: this is the subject of the present invention.